Otitis media, which is the most common disease in the pediatric population, is believed clinically to cause a deterioration of balance. Despite this prevalence of otitis media, its effect on balance function has not been systematically evaluated. The overall objectives of this proposal are to study vestibular and balance function and motor development in a cohort of 150 children ages 2 to 7 years, and determine the short and long-term effects of otitis media with effusion on the balance and vestibular system. This study will prospectively establish: 1) normative age-appropriate vestibular and balance data and evaluate the maturation of the vestibular and balance system in a cohort of children with documented middle ear history since birth; 2) the effect of otitis media with effusion, including the effect of unilateral vs. bilateral effusion, and tympanostomy tube insertion on vestibular and balance function and motor function; and 3) which aspects of vestibular functin are affected by otitis media and possible adaptive mechanisms.